Rat hepatoma cells in tissue culture grown on hollow fiber semipermeable membranes have been shown to function as an artificial liver in a circumfusion culture system by their uptake, glucuronylation and excretion of bilirubin. It is proposed to study bilirubin metabolism and other liver-related functions by the artificial liver in an extracorporeal circuit with the rat. BIBLIOGRAPHIC REFERENCES: Wolf, C.F.W. and B.E. Munkelt, "Bilirubin Conjugation by an Artificial Liver Composed of Cultured Cells and Synthetic Capillaries", Transactions of the American Society for Artificial Internal Organs, XXI, 16-27 (1975). Five copies are enclosed, and copies are attached to this progress report (Section 3.E.4).